This removes it from the AST and largely replaces it with AnyObject
at the SIL and IRGen layers. Some notes:
- Reflection still uses the notion of "unknown object" to mean an
object with unknown refcounting. There's no real reason to make
this different from AnyObject (an existential containing a
single object with unknown refcounting), but this way nothing
changes for clients of Reflection, and it's consistent with how
native objects are represented.
- The value witness table and reflection descriptor for AnyObject
use the mangling "BO" instead of "yXl".
- The demangler and remangler continue to support "BO" because it's
still in use as a type encoding, even if it's not an AST-level
Type anymore.
- Type-based alias analysis for Builtin.UnknownObject was incorrect,
so it's a good thing we weren't using it.
- Same with enum layout. (This one assumed UnknownObject never
referred to an Objective-C tagged pointer. That certainly wasn't how
we were using it!)
* [SILOptimizer] Don't diagnose infinite recursion if a branch terminates the program
This patch augments the infinite recursion checker to not warn if a
branch terminates, but still warns if a branch calls into something with
@_semantics("programtermination_point"). This way, calling fatalError
doesn't disqualify you for the diagnostic, but calling exit does.
This also removes the warning workaround in the standard library, and
annotates the internal _assertionFailure functions as
programtermination_points, so they get this treatment too.
* Fix formatting in SILInstructions.cpp
* Re-add missing test
This patch augments the infinite recursion checker to not warn if a
branch terminates, but still warns if a branch calls into something with
`@_semantics("arc.programtermination_point")`. This way, calling `fatalError`
doesn't disqualify you for the diagnostic, but calling `exit` does.
This also removes the warning workaround in the standard library, and
annotates the internal _assertionFailure functions as
`programtermination_point`s, so they get this treatment too.
- Update the Pygments lexer we use for parsing Swift-like code.
- State more explicitly which highlighting should be used in which
code blocks.
- Disable highlighting altogether in certain cases (such as SIL.rst,
which has equal amounts grammar and SIL excerpts).
This should fix the warnings-as-error issues coming from Sphinx > 1.3.4.
Based on a patch by Jeremy Fergason!
https://bugs.swift.org/browse/SR-620
If this semantic tag is applied to a function, then we know that:
- The function does not touch any reference counted objects.
- After the function is executed, all reference counted objects are leaked
(most likely in preparation for program termination).
This allows one, when performing ARC code motion, to ignore blocks that contain
an apply to this function as long as the block does not have any other side
effect having instructions.
I have wanted to do this for a while but was stymied by lacking the ability to
apply multiple @_semantics attributes. This is now committed to trunk so I added
this attribute instead of pattern matching against fatalError (since there could
be other functions with this property).
rdar://19592537
There's a buggy SIL verifier check that was previously tautological,
and it turns out that it's violated, apparently harmlessly. Since it
was already doing nothing, I've commented it out temporarily while
I figure out the right way to fix SILGen to get the invariant right.
I also added a placeholder for ARC optimization docs. I wanted anyone
reading about swift ARC optimization to run across my discussion on
correctness w.r.t. COW.
Swift SVN r27890
